class_docstr: MFCC extraction test.
code: def test_mfcc(self):
      wav_path = str(Path(PACKAGE_OPS_DIR).joinpath("data/sm1_cln.wav"))
  
      with self.cached_session(use_gpu=False, force_gpu=False):
          read_wav = ReadWav.params().instantiate()
          input_data, sample_rate = read_wav(wav_path)
          config = {"use_energy": True}
          mfcc = Mfcc.params(config).instantiate()
          mfcc_test = mfcc(input_data, sample_rate)
  
          self.assertEqual(tf.rank(mfcc_test).eval(), 3)
  
          real_mfcc_feats = np.array(
              [
                  [
                      9.819611,
                      -30.58736,
                      -7.088838,
                      -10.67966,
                      -1.646479,
                      -4.36086,
                  ],
                  [
                      9.328745,
                      -30.73371,
                      -6.128432,
                      -7.930599,
                      3.208357,
                      -1.086456,
                  ],
              ]
          )
  
          self.assertAllClose(
              np.squeeze(mfcc_test.eval()[0, 0:2, 0:6]),
              real_mfcc_feats,
              rtol=1e-05,
              atol=1e-05,
          )
  
file_path: delta/delta/data/frontend/mfcc_test.py
imports: import delta.compat
  import os
  from pathlib import Path
  from delta.data.frontend.read_wav import ReadWav
  from delta.data.frontend.mfcc import Mfcc
  import numpy
  from core.ops import PACKAGE_OPS_DIR
label_desc: Use image node_id 1 for calling the MfccTest obj's underlying member method code with example usage: obj.test_mfcc() without return types